A gas leak is believed to have been the cause of an explosion in a Swieqi residence on Monday.
The police said on Tuesday that a 69-year-old woman was seriously injured.
The blast took place at 8.15am in a house in Triq is-Siegħ. The woman suffered burns.
She was assisted by the police and rescuers from the Civil Protection Department and taken to hospital.
Investigations are continuing.